interface riscv_npu_if(input logic clk, rst_n);
  logic        mem_req, mem_we, mem_ack;
  logic [31:0] mem_addr, mem_wdata, mem_rdata;

  clocking cb @(posedge clk);
    output mem_req, mem_we, mem_addr, mem_wdata;
    input  mem_ack, mem_rdata;
  endclocking
endinterface